The present invention relates to a pruning machine. More particularly, the invention relates to a pruning machine which can be mounted to a tractor or the like and which is arranged for pruning trellised vines, fruit trees or other vegetation.
Pruning is a necessary part of most commercial fruit and plant harvesting enterprises. Pruning at particular points in a plant""s growth cycle results in optimized production of fruit or other harvestable matter.
Manual pruning of vines is a particularly time consuming and labour intensive process. Accordingly, machines have been developed to prune vines and thereby increase overall efficiency. Unfortunately, due to the fact that trellised vines are grown along support wires the orientation of the vines themselves and the presence of support wires and support posts make them extremely difficult to successfully prune mechanically.
When pruning vines, it is critical that no damage occurs to the main trunk of the vines or the cordons which extend along the support wires. If they are damaged during pruning there will be reduced harvest or the possibility that the vine will actually die. During pruning it is only the canes which extend from the cordons which should be removed. One of the problems with current mechanical pruning machines is that they may damage the cordons or may themselves be damaged when they strike the support posts which support the support wires. Another problem is that they cannot cut both below and above a cordon wire without damaging the cordon or the vine trunk. The present invention seeks to provide an improved pruning machine which addresses at least some of the abovementioned problems.
According to a first aspect of the present invention there is provided a pruning machine for pruning vegetation, said machine including a frame arranged for connection to a tractor or the like so as to enable the machine to be moved along the vegetation to be pruned, a first pruning assembly arranged for attachment to the frame, the first pruning assembly including first and second pruning apparatus arranged so that in use they can be positioned either side of a vegetation support wire on which required vegetation is located, said first and second pruning apparatus being arranged to prune non-required vegetation extending substantially above and/or below the support wire.
According to a second aspect of the present invention there is provided a pruning machine for pruning vegetation growing on at least a first and a second vertically-spaced support wires, said machine including a first pruning assembly having at least a first pair of spaced pruning apparatus, said spaced pruning apparatus being arranged so that during use they are arranged to prune non-required vegetation extending between said at least first and second spaced support wires to thereby create a window of cleared non-required vegetation between said vertically-spaced support wires.
Preferably, the first pruning assembly includes a shaft on which said first pair of spaced pruning apparatus are mounted. Each pruning apparatus preferably includes a first pruning plate having a central axis and an outer edge, a first set of blades on the first pruning plate and protruding outwardly from the outer edge. A second pruning plate is also provided and is arranged so that the respective central axes and outer edges of the pruning plates substantially coincide. A second set of blades is located on the second pruning plate. The blades protrude outwardly from the second pruning plate outer edge. In operation, the first set of blades rotates relative to the second set of blades so that scissor-like cutting actions are formed between them. As an optional feature, the direction of rotation of the first set of blades may be reversible. In normal use, rotation is in either the clockwise or counter-clockwise direction, but the direction of rotation may be reversed. This can assist in cleaning debris from the blades, and it can also be used to extend blade life, if the blades are symmetrical in shape and can cut in either direction.
Preferably, the blades on the first pruning plate and/or the blades on the second pruning plate taper from broader width at the outer edge of the respective pruning plates to a narrow width at the point furthest from the central axis.
One of the functions performed by the pruning plate or plates which rotates is to act as a flywheel, so that a steady weighted force is applied to the cutting effect of the blades.
The first pruning plate may be of any suitable shape and configuration. A preferred shape is a disc shape but other shapes such as polygonal shapes, star shapes and cartwheel shapes are also suitable. It is preferred that the first pruning plate be flat although other shapes such as a bowl shape are also suitable.
The second pruning plate may be of any suitable shape and configuration. The preferred shapes and features are similar to those for the first pruning plate. The second pruning plate is fixed while the first pruning plate rotates. The second pruning plate may be semicircular or some other shape which is not continuous in the full part of the rotating plates, because it is only necessary that fixed blades be provided at the locations at which cutting actually occurs.
The complete details of one form of the pruning apparatus are incorporated herein by reference to the applicant""s earlier international patent application number PCT/AU98/00002.
Preferably, the first pruning assembly also includes a first protections plate arranged to be mounted on the shaft so that it is located between said first support wire and said first pair of spaced pruning apparatus. The first protection plate being arranged to prevent inadvertent damage to the first support wire or to required vegetation growing along said support wire.
The first protection plate may be of any suitable shape and configuration. A preferred shape is a disc shape. The disc is typically mounted on the shaft so that it can spin freely thereabout during operation of the pruning machine. The protection plate may be constructed in two parts which are bolted to a mounting collar mounted on the shaft. This allows for easy removal of the protection plate without disassembling the machine.
In a preferred arrangement of the invention, a first protection plate is provided so that in use it is located substantially above said first support wire and a second protection plate is mounted on the shaft so that in use it is located substantially below said first support wire. In this manner the vine cordon located along the support wire is protected from inadvertent damage during pruning.
As an alternative, or in addition, to the protection plate, a guard cage may be mounted about each pruning apparatus. The guard cage is secured to a collar mounted on the drive shaft The guard cage is arranged to prevent inadvertent damage to the posts supporting the support wires and/or the substantially vertically extending trunk of the vegetation. The guard cage is typically divided into two halves which can be secured to the collar by bolts.
A guard cage preferably consists of an upper part, a lower part, and a plurality of bars extending between the top and bottom parts, shielding the blades of the pruning apparatus. The bars may extend directly downwards from the upper part to the lower part, but it is preferred that they be oriented at an angle to the vertical and spaced sufficiently closely that a vertical post or vine trunk cannot inadvertently pass between adjacent bars and come into contact with the blades.
Preferably, additional pruning apparatus are mounted on said shaft so that non-required vegetation below said first support wire and above said second support wire can also be pruned. In situations where there are more than said first and second support wires it will be appreciated by those skilled in the art that additional pruning apparatus may be incorporated.
Preferably, the pruning assembly is arranged to be mounted on a movable frame. The movable frame in turn being mounted to a support frame arranged for attachment to a tractor or the like. The support frame is preferably attached to the tractor or the like in a manner whereby the pruning machine can be moved between an operative position and a transport position. In the transport position the pruning machine is preferably located in front of or directly behind the tractor or the like.
The movable frame is arranged so that the pruning assembly can be moved away and toward the vegetation to be pruned so that guide posts, trunks of vegetation and other obstacles can be avoided. The movable frame thereby moves between a working position in which it prunes vegetation and a non-working position in which it is clear of the vegetation. Typically, movement of the movable frame to avoid obstacles is signaled by an arrangement of electronic eyes or limit switches which detect the presence of an obstacle. In response to such a signal, an accumulator or other alternative device is operated to cause pivotal movement of the movable frame away from the obstacle so that the pruning apparatus avoids contact therewith. Once the obstacle is cleared the accumulator or other alternative device is signaled and a biasing means serves to pivot the movable frame and thereby return it to the working positions.
To enable the pruning machine to prune vegetation on angled guides such as vines on a v-trellis, the pruning assembly and/or the support frame and/or the connection to the tractor or the like is capable of being tilted so as to accommodate the angled guides. It is envisaged that with such an arrangement, the longitudinal axis of the shaft of each pruning assembly will be capable of adopting an orientation of between vertical and approximately 45 degrees to the vertical.
In a preferred embodiment, the pruning machine includes first and second pruning assemblies with their respective shafts extending substantially parallel to each other. The pruning apparatus of each pruning assembly are spaced along their respective shafts. Preferably, each shaft has correspondingly positioned pruning apparatus which are just offset with each other a sufficient distance such that their respective blades do not contact.
Furthermore, the protection plates of each pruning assembly are also preferably offset relative to one another so that an edge portion of the protection plates of the first pruning assembly overlie an edge portion of a corresponding protection plate of the second pruning assembly.
Preferably, a pruning apparatus or multiples thereof are additionally provided to enable pruning of non-required vegetation extending substantially horizontally from the support wires. Thus, such a set of additional pruning apparatus would enable pruning of vegetation in a plane extending substantially parallel to the plane of the vertically-spaced support wires.
According to a third aspect of the present invention there is provided a method of pruning vegetation using a pruning machine in accordance with the first and second aspects of the invention.